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Diffstat (limited to 'compiler-rt/lib/builtins/floatsidf.c')
-rw-r--r-- | compiler-rt/lib/builtins/floatsidf.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/compiler-rt/lib/builtins/floatsidf.c b/compiler-rt/lib/builtins/floatsidf.c new file mode 100644 index 000000000000..2c66167d794d --- /dev/null +++ b/compiler-rt/lib/builtins/floatsidf.c @@ -0,0 +1,57 @@ +//===-- lib/floatsidf.c - integer -> double-precision conversion --*- C -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements integer to double-precision conversion for the +// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even +// mode. +// +//===----------------------------------------------------------------------===// + +#define DOUBLE_PRECISION +#include "fp_lib.h" + +#include "int_lib.h" + +COMPILER_RT_ABI fp_t __floatsidf(int a) { + + const int aWidth = sizeof a * CHAR_BIT; + + // Handle zero as a special case to protect clz + if (a == 0) + return fromRep(0); + + // All other cases begin by extracting the sign and absolute value of a + rep_t sign = 0; + if (a < 0) { + sign = signBit; + a = -a; + } + + // Exponent of (fp_t)a is the width of abs(a). + const int exponent = (aWidth - 1) - __builtin_clz(a); + rep_t result; + + // Shift a into the significand field and clear the implicit bit. Extra + // cast to unsigned int is necessary to get the correct behavior for + // the input INT_MIN. + const int shift = significandBits - exponent; + result = (rep_t)(unsigned int)a << shift ^ implicitBit; + + // Insert the exponent + result += (rep_t)(exponent + exponentBias) << significandBits; + // Insert the sign bit and return + return fromRep(result | sign); +} + +#if defined(__ARM_EABI__) +#if defined(COMPILER_RT_ARMHF_TARGET) +AEABI_RTABI fp_t __aeabi_i2d(int a) { return __floatsidf(a); } +#else +COMPILER_RT_ALIAS(__floatsidf, __aeabi_i2d) +#endif +#endif |